scholarly journals The brown algae Saccharina japonica and Sargassum horneri exhibit species-specific responses to synergistic stress of ocean acidification and eutrophication

2021 ◽  
Author(s):  
Yuxin Liu ◽  
Jiazhen Cao ◽  
Yaoyao Chu ◽  
Yan Liu ◽  
Qiaohan Wang ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Saccharina Japonica ◽  
Marine Macroalgae ◽  
Sargassum Horneri ◽  
Chlorophyll Contents ◽  
Main Culture ◽  
Increasing Risk ◽  
Species Specific ◽  
Tissue Nitrogen ◽  
Great Damage

Ocean acidification and eutrophication are two important environmental stressors. They inevitably impact marine macroalgae, and hence the coastal ecosystem of China. Saccharina japonica, as the main culture species in China, is suffering the harmful golden tide caused by Sargassum horneri. However, it remains unclear whether the detrimental effects of S. horneri on S. japonica cultivation become more severe in future acidified and eutrophic scenario. In this study, we respectively investigated the effects of pCO2 (400 μatm and 1000 μatm) and nutrients (non-enriched and enriched seawater) on the growth, photosynthesis, respiration, chlorophyll contents, and tissue nitrogen of S. japonica and S. horneri. Results indicated that enrichment of nutrients contributed S. horneri to utilize HCO3-. The carbon acquisition pathway shifted from HCO3- to CO2 in S. japonica, while S. horneri remained using HCO3- regulated by nutrient enrichment. S. horneri exhibited better photosynthetic traits than S. japonica, with a higher level of net photosynthetic rate and chlorophyll contents at elevated pCO2 and enriched nutrients. Tissue nitrogen also accumulated richly in the thalli of S. horneri under higher pCO2 and nutrients. Significant enhancement in growth was only detected in S. horneri under synergistic stress. Together, S. horneri showed competitive dominance in current study. These findings suggest that increasing risk of golden tide in acidified and eutrophic ocean can most likely result in great damage to S. japonica cultivation.

scholarly journals Differential suppression of rice weeds by allelopathic plant aqueous extracts

2013 ◽  
Vol 31 (1) ◽  
pp. 21-28 ◽  
Author(s):  
A Khaliq ◽  
A Matloob ◽  
M.B Khan ◽  
A Tanveer
Keyword(s):  
Seedling Growth ◽  
Weed Management ◽  
Biomass Accumulation ◽  
Cyperus Rotundus ◽  
Interactive Effects ◽  
Aqueous Extracts ◽  
Weed Species ◽  
Test Species ◽  
Chlorophyll Contents ◽  
Species Specific

Herbicidal potential of different plant aqueous extracts was evaluated against early seedling growth of rice weeds in pot studies. Plant aqueous extracts of sorghum (Sorghum bicolor), sunflower (Helianthus annuus), brassica (Brassica compestris), mulberry (Morris alba), eucalyptus (Eucalyptus camaldunensis), and winter cherry (Withania somnifera) at a spray volume of 18 L ha-1 each at the 2-4 leaf stage of rice weeds viz horse purslane (Trianthema portulacastrum) [broad-leaf], jungle rice (Echinochloa colona), and E. crus-galli (barnyard grass) [grasses] and purple nut sedge (Cyperus rotundus) and rice flat sedge (C. iria) [sedges]. The results showed significant interactive effects between plant aqueous extracts and the tested weed species for seedling growth attributes depicting that allelopathic inhibition was species-specific. Shoot and root length, lateral plant spread, biomass accumulation, and leaf chlorophyll contents in test species were all reduced by different extracts. The study suggested the suppressive potential of allelopathic plant aqueous extracts against rice weeds, and offered promise for their usefulness as a tool for weed management under field conditions.

Climate change and ocean acidification effects on seagrasses and marine macroalgae

2012 ◽  
Vol 19 (1) ◽  
pp. 103-132 ◽  
Author(s):  
Marguerite Koch ◽  
George Bowes ◽  
Cliff Ross ◽  
Xing-Hai Zhang
Keyword(s):  
Climate Change ◽  
Ocean Acidification ◽  
Marine Macroalgae

scholarly journals Supplemental Material: Ocean acidification during the early Toarcian extinction event: Evidence from boron isotopes in brachiopods

2020 ◽  
Author(s):  
Tamás Müller ◽  
et al.
Keyword(s):  
Ocean Acidification ◽  
Specific Effect ◽  
Boron Isotopes ◽  
Carbonate Chemistry ◽  
Additional Information ◽  
Model Sample ◽  
Calibration Methods ◽  
Extinction Event ◽  
Age Model ◽  
Species Specific

Detailed information on the applied geochemical and calibration methods, carbonate chemistry models, age model, sample preservation, and additional information about species-specific effect on δ<sup>11</sup>B fractionation in brachiopods.<br>

scholarly journals Short-term responses to ocean acidification: effects on relative abundance of eukaryotic plankton from the tropical Timor Sea

2020 ◽  
Author(s):  
Janina Rahlff ◽  
Sahar Khodami ◽  
Lisa Voskuhl ◽  
Matthew P. Humphreys ◽  
Christian Stolle ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Community Composition ◽  
Hypervariable Region ◽  
18S Rrna Gene ◽  
Marine Biodiversity ◽  
Rrna Gene ◽  
Tropical Regions ◽  
Timor Sea ◽  
Decreasing Ph ◽  
Species Specific

ABSTRACTAnthropogenic carbon dioxide (CO2) emissions drive climate change and pose one of the major challenges of our century. The effects of increased CO2 in the form of ocean acidification (OA) on the communities of marine planktonic eukaryotes in tropical regions such as the Timor Sea are barely understood. Here, we show the effects of high CO2 (pCO2=1823±161 μatm, pHT=7.46±0.05) versus in situ CO2 (pCO2=504±42 μatm, pHT=7.95±0.04) seawater on the community composition of marine planktonic eukaryotes immediately and after 48 hours of treatment exposure in a shipboard microcosm experiment. Illumina sequencing of the V9 hypervariable region of 18S rRNA (gene) was used to study the eukaryotic community composition. Down-regulation of extracellular carbonic anhydrase occurred faster in the high CO2 treatment. Increased CO2 significantly suppressed the relative abundances of different eukaryotic operational taxonomic units (OTUs), including important primary producers. These effects were consistent between abundant (DNA-based) and active (cDNA-based) taxa after 48 hours, e.g., for the diatoms Trieres chinensis and Stephanopyxis turris. Effects were also very species-specific among different diatoms. Planktonic eukaryotes showed adaptation to the CO2 treatment over time, but many OTUs were adversely affected by decreasing pH. OA effects might fundamentally impact the base of marine biodiversity, suggesting profound outcomes for food web functioning in the future ocean.

scholarly journals Predicting potential impacts of ocean acidification on marine calcifiers from the Southern Ocean

2020 ◽  
Author(s):  
Blanca Figuerola ◽  
Alyce M. Hancock ◽  
Narissa Bax ◽  
Vonda Cummings ◽  
Rachel Downey ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Ocean Acidification ◽  
Industrial Revolution ◽  
Negative Impact ◽  
Meta Analysis ◽  
Mineralogical Composition ◽  
Critical Issue ◽  
Biological Traits ◽  
Negative Effects ◽  
Species Specific

AbstractUnderstanding the vulnerability of marine calcifiers to ocean acidification is a critical issue, especially in the Southern Ocean (SO), which is likely to be the one of the first, and most severely affected regions. Since the industrial revolution, ~30% of anthropogenic CO2 has been absorbed by the oceans. Seawater pH levels have already decreased by 0.1 and are predicted to decline by ~ 0.3 by the year 2100. This process, known as ocean acidification (OA), is shallowing the saturation horizon, which is the depth below which calcium carbonate (CaCO3) dissolves, likely increasing the vulnerability of many marine calcifiers to dissolution. The negative impact of OA may be seen first in species depositing more soluble CaCO3 mineral phases such as aragonite and high-Mg calcite (HMC). These negative effects may become even exacerbated by increasing sea temperatures. Here we combine a review and a quantitative meta-analysis to provide an overview of the current state of knowledge about skeletal mineralogy of major taxonomic groups of SO marine calcifiers and to make predictions about how OA might affect different taxa. We consider their geographic range, skeletal mineralogy, biological traits and potential strategies to overcome OA. The meta-analysis of studies investigating the effects of the OA on a range of biological responses such as shell state, development and growth rate shows response variation depending on mineralogical composition. Species-specific responses due to mineralogical composition suggest taxa with calcitic, aragonitic and HMC skeletons may be more vulnerable to the expected carbonate chemistry alterations, and low magnesium calcite (LMC) species may be mostly resilient. Environmental and biological control on the calcification process and/or Mg content in calcite, biological traits and physiological processes are also expected to influence species specific responses.

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